A case of Williams syndrome with suspected coexisting ectopic aldosterone-producing tumor in the liver.

Williams syndrome (WS) is a rare genetic disorder, characterized by a constellation of medical and cognitive findings, with a hallmark feature of generalized arteriopathy presenting as stenoses of elastic arteries and hypertension. WS is a disease with a high frequency of hypertension but the renin-aldosterone system in WS cases has not been studied at all. If a patient with WS had hypertension and severe hypokalemia, low PRA and high ARR, the coexistence of primary aldosteronism (PA) should be considered. Adrenal rest tumors are thought to arise from aberrant adrenal tissues and are a rare cause of PA. Hepatic adrenal rest tumor (HART) should be considered in the differential diagnosis when detecting a mass in the right hepatic lobe. Segmental adrenal venous sampling could contribute to distinguish adrenal tumors from HART.